Maintenance holes to provide for access to telephone cables, power cables, gas lines and the like, as usually installed in streets, are covered by heavy metal covers seated on a stepped rim of the manhole. Under emergency conditions, it may be necessary to leave off the heavy metal cover since it may be necessary to run cables, hoses or the like around the edge of the manhole. These cables, hoses, and also air supply tubes for personnel working underground, may be in place for a considerable period of time. If, during that time, it starts to rain, water or snow will fall through the opening of the maintenance hole. If the maintenance hole is installed in a location where water runs down the street, a considerable amount of water may accumulate within the manhole. If electrical or other moisture-sensitive equipment is located within the maintenance hole, damage may result. Further, damage may become extensive if the maintenance hole is connected by conduits to adjacent buildings. Water may run through the conduits into the basement of the buildings, causing basement flooding. The maintenance hole cover usually cannot be replaced, even temporarily, because the heavy metal cover might cut into electrical cables, gas hoses or the like, which are run, under emergency conditions, over the edge of the manhole.